[3][4] In summer 2016, Čumić moved to Serbian SuperLiga side Metalac Gornji Milanovac and signed a three-year contract with new club.

[5] He made his SuperLiga debut on 29 July 2016, replacing Walberto Caicedo in 71 minute of the match against Red Star Belgrade.

[7] On 19 December 2019, Olympiacos officially announced the signing of Čumić for a transfer fee estimated in the region of €500,000; he would remain in his former club until the end of the 2019–20 season.

[11] On 14 September 2023, Čumić signed a four-year deal with Russian Premier League club Rubin Kazan, for an undisclosed fee.

[12] Čumić was called up to the senior Serbia national team for the first time in June 2023 for a friendly against Jordan, but remained on the bench in the game.